Egg Carton with Separate Base and Lid Configurations and Moisture Venting

ABSTRACT

A rectangular perimeter egg carton comprising:
         a lid, and a base separate from the lid, wherein the lid and base are assembled together to from a closed egg carton,   the base having a top wall and a rectangular array of recessed base cells arranged in rows and columns depending from the top wall, each base cell having an open top end, a sidewall and a closed bottom wall and being sized and shaped to hold one egg in a generally upright position with the long axis of the egg disposed in a vertical direction transverse to a base reference plane in which the bottom walls of the base cells reside;   the base and lid having respective mating rectangular perimeter edges, including opposing front and rear side edges and opposing left and right side edges, that mate with each other in a closed position to from the rectangular perimeter egg carton for enclosing an egg in each of the respective cells; and   a plurality of spaced apart venting ports formed in each of the perimeter side edges of one or more of the base and lid perimeters for releasing moisture from the closed egg carton.

FIELD OF THE INVENTION

The present invention relates to an egg carton having a separate base and lid that together form a closed egg carton, which can be provided in multiple configurations and with moisture venting.

BACKGROUND

Egg cartons are subjected to multiple adverse mechanical forces and environmental conditions during filling, handling and transport between distribution centers, store shelves, and the ultimate consumer's home. They typically encounter automated equipment for filling, packaging, loading, unloading, stacking, restacking and transport. During each of these encounters, the goal is to resist egg breakage by stabilizing and holding the eggs in a protected environment, in a carton that can be manufactured in a cost-effective manner.

Thus, many factors are taken into consideration in the design of egg cartons. Egg protection, resistance to stress or force, stack-ability, transportability, moisture-resistance, aesthetic appearance, print surface area, weight, nestability/denest-ability, adaptability to accommodate various size eggs, and consistent manufacturing are factors which may be considered to varying degrees in the design of an egg carton.

Condensation is a common egg handling issue. The problem occurs when eggs are packed, placed into refrigeration and then again throughout the transportation process whenever the filled egg cartons are exposed to large temperature variations. High humidity in southern locations are especially detrimental to carton integrity due to excess moisture condensation.

Thus, there is need for an improved egg carton construction to provide better egg protection while encountering the adverse mechanical forces and environmental changes that typically occur during filing, packaging, transportation and storage. At the same time, there is a need to manufacture such cartons in a cost-effective manner and to maintain overall carton dimensions within standard case sizes to avoid a redesign of the existing handling equipment.

SUMMARY OF THE INVENTION

The most common egg carton for consumer purchase (e.g., at a grocery store) comprises a one-piece mating lid and base portions having a hinged connection for opening and closing the lid and base. The standard carton provides a rectangular 2×6 array of 12 egg cells, and is composed of one material, e.g., cardboard (paperboard), clear plastic (PET), or opaque plastic foam (polystyrene). These cartons are easy to manufacture, fill, pack and ship (in larger rectangular cartons), unpack and display in a refrigerated store case (typically packed side-by-side and vertically in a 3D stack), allow repeated opening/closing by the consumer, and minimize the amount of storage space in the consumer's refrigerator. The cartons have various features to protect and cushion the eggs during all of these steps of filling, shipping, handling and display.

It would be advantageous to provide an egg carton that differs from the standard carton such that the carton itself can be made from different materials and/or in different configurations. In one embodiment the different materials and/or configurations enable improved functionality over the standard one-piece lid and base made from a single material. In one embodiment the different materials and/or configurations are used to differentiate one source of eggs from another and yet maintain many of the same functional attributes.

It would also be advantageous to provide an egg carton that can provide effective moisture venting through increased evaporation. The most common package design utilizes a hinged lid, limiting the potential ventilation to three sides of the package.

According to the present invention, a new design for an egg carton is provided that can accommodate the use of different material configurations for the base and lid, and/or that can provide ventilation on all four perimeter edges of a rectangular carton formed a separate base and lid. The full perimeter venting significantly increases evaporation and minimizes the negative impact of condensation. The use of different materials for the base and lid can further enhance the performance in minimizing adverse effects from condensation and other functional attributes.

In accordance with one embodiment of the invention a rectangular perimeter egg carton comprising:

a lid, and a base separate from the lid, wherein the lid and base are assembled together to from a closed egg carton,

the base having a top wall and a rectangular array of recessed base cells arranged in rows and columns depending from the top wall, each base cell having an open top end, a sidewall and a closed bottom wall and being sized and shaped to hold one egg in a generally upright position with the long axis of the egg disposed in a vertical direction transverse to a base reference plane in which the bottom walls of the base cells reside;

the base and lid having respective mating rectangular perimeter edges, including opposing front and rear side edges and opposing left and right side edges, that mate with each other in a closed position to from the rectangular perimeter egg carton for enclosing an egg in each of the respective cells; and

a plurality of spaced apart venting ports formed in each of the perimeter side edges of one or more of the base and lid perimeters for releasing moisture from the closed egg carton.

In accordance with one embodiment of the invention the venting ports each comprise a groove formed in the base along each of the base perimeter edges.

In accordance with one embodiment of the invention there is at least one venting port disposed in the sidewall of each cell of the base.

In accordance with one embodiment of the invention the venting ports each comprise an outwardly projecting grooved surface, extending outwardly from the outer surface of the cell sidewall.

In accordance with one embodiment of the invention the lid and base perimeter edges include releasable connectors for removably attaching the lid to the base to temporarily seal an egg in each cell of the closed carton.

In accordance with one embodiment of the invention the releasable connectors are disposed between each pair of adjacent cells on each of the mating perimeter edges.

In accordance with one embodiment of the invention the releasable connectors comprise snap-fit tabs on the lid perimeter edges that extend over the base perimeter edges.

In accordance with one embodiment of the invention at least one of the venting ports is disposed between each adjacent pair of the releasable connectors.

In accordance with one embodiment of the invention the sidewalls of two adjacent cells form a cell divider which prevents contact between eggs in the adjacent cells.

In accordance with one embodiment of the invention the base includes a base top wall forming a flat planar surface that extends between the open top ends of the cells and forms the base perimeter edges.

In accordance with one embodiment of the invention the base includes cell posts disposed between four adjacent cells in the rectangular array of cells.

In accordance with one embodiment of the invention the lid comprises a lid top wall disposed parallel to the base reference plane on which the cell base walls reside, and lid sidewalls extending downwardly between the lid top wall and the lid perimeter edges to form an interior chamber for enclosing an upper portion of the eggs disposed in the cells of the base.

In accordance with one embodiment of the invention the base cell posts extend above the base perimeter edges and into the interior chamber and mate with an inner surface of the lid top wall to strengthen the closed egg carton.

In accordance with one embodiment of the invention the sidewalls of the base cells extend the full height of the eggs disposed in the cells, and the lid comprises a flat planar lid top wall that is sealed about its perimeter edges to the mating perimeter edges of the base.

In accordance with one embodiment of the invention the sidewalls of the base cells extend less than the full height of the eggs disposed in the cells, and wherein the lid comprises a lid top wall disposed parallel to the base reference plane on which the cell base walls reside, and lid sidewalls extending downwardly between the lid top wall and the lid perimeter edges to form an interior chamber for enclosing an upper portion of the eggs disposed in the cells of the base.

In accordance with one embodiment of the invention the array of cells comprises one of a 2×3, 2×4, 2×5, 2×6, 3×3, 3×4, 3×5, 3×6, 4×4, 4×5, 4×6, 5×5, 5×6, or 6×6 rectangular matrix of cells.

In accordance with one embodiment of the invention the base and lid are formed of different materials.

In accordance with one embodiment of the invention the base is formed of molded pulp fiber, and the lid is formed of a solid plastic.

In accordance with one embodiment of the invention the different materials are solid plastic, foamed plastic, and pulp fiber.

In accordance with one embodiment of the invention the plastic is one or more of polystyrene, polyester, polyethylene, or polylactic acid, including polymers, copolymers, mixtures and blends thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrate one embodiment of an egg carton having a separate base and lid according to the present invention, and having mating rectangular perimeters with moisture venting provided on all four sides of the rectangular carton, wherein:

FIG. 1 is an exterior top perspective view of the assembled base and lid forming the closed egg carton, as viewed from the front and right sides of the carton, here made of two different materials for the base and lid, the base being made of pulp fiber, and the lid being made of a transparent solid plastic such as PET, showing an enlarged flat top wall label panel area on the lid, and with moisture venting portions disposed at the perimeter of the base on each of the opposing front and rear, and opposing right and left sides, respectively;

FIG. 2 is a right-side end plan view of the closed egg carton of FIG. 1 ;

FIG. 3 is a front-side plan view of the closed egg carton of FIG. 1 ;

FIG. 4 is a length-wise, vertical mid-cross-sectional view of the closed egg carton of FIG. 1 ;

FIG. 5 is a perspective view of the separate base and lid of FIG. 1 , unassembled, showing the interiors of each;

FIGS. 6-8 illustrate another embodiment of an egg carton having a separate base and lid that includes mating rectangular perimeters with the moisture venting provided on all four sides of the rectangular carton according to the present invention, here with a base having full depth egg cells and with a flat top lid closure bonded to the base at the mating perimeters, wherein:

FIG. 6 is an exterior top perspective view of the assembled base and lid;

FIG. 7 is a top perspective view of the base only of FIG. 6 , showing the interior of the base providing a rectangular array of egg cells;

FIG. 8 is an front-side plan view of the base only of FIG. 6 ;

FIG. 9 is a bottom plan view of the assembled base and lid of FIG. 6 , showing the verting portions on all four sides of the base perimeter and the mating perimeters of the base and lid;

FIGS. 10-12 illustrate another embodiment of an egg carton having a separate base and lid in another configuration according to the present invention, which that can include the moisture venting feature (not shown), and with a base having full depth egg cells and with a lid closure having a flat top wall and depending therefrom four flat front, rear and opposing end walls that provide additional flat labeling area on the lid, wherein:

FIG. 10 is an exterior top perspective view of the assembled base and lid;

FIG. 11 is a lengthwise vertical, mid-cross sectional view of the assembled base and lid of FIG. 10 ;

FIG. 12 is a bottom plan view of the assembled base and lid of FIG. 10 .

DETAILED DESCRIPTION

First Embodiment of Egg Carton with Separate Lid and Base, and Moisture Venting Ports on all Four Sides of the Rectangular Carton (FIGS. 1-5 )

The present invention is directed to a two-piece egg carton, comprising separate base and lid, that when assembled in a stacked vertical alignment (with the lid on top of the base), form a closed egg carton.

FIGS. 1-5 illustrate one embodiment of the invention comprising an egg carton 10 having a separate base 30 and lid 60. The new base, lid and carton assembly are configured for holding eggs in a rectangular array of egg cells 31 (arranged in linear rows and transverse linear columns). The base and lid have mating rectangular perimeters 30P, 60P with moisture venting ports 20 provided on all four sides of the rectangular carton 10 (on each of the four opposing front and rear sides 10F, 10R, and right and left sides 10RS. 10LS, respectively). The venting ports may be provided on either or both of the base and lid perimeters; in the first embodiment of FIGS. 1-5 , the venting ports 20 are disposed on the base perimeter 30P. The base and lid are made of two different materials, the base 30 being made of pulp fiber, and the lid 60 being made of a transparent solid plastic, such as polyethylene terephalate (PET). The lid includes a flat panel top wall 71 and a depending sidewall 72 on all four sides, forming an empty interior cavity 73 below the top wall. Base posts 32 are provided on the base for supporting the lid over the base, including five linearly aligned extended height base posts 33 supporting the bottom surface of the flat panel top wall 71. These and other features of the present invention will be apparent from the following description of various embodiments.

FIGS. 1-3 illustrate exterior views of the base tray 30 and lid tray 60 assembled to form a closed carton 10 according to one embodiment, showing the venting ports 20 on all four opposing side edges of the rectangular carton 10. Each of the base tray and lid tray have a generally rectangular perimeter 30P, 60P in horizontal cross section, that when assembled form a generally rectangular carton perimeter 10P in horizontal cross section, with mating opposing front and rear base/lid/carton edges 30F/60F/10F and 30R/60R/10R, and mating opposing right and left side base/lid/carton edges 30RS/60RS/10RS and 30LS/60LS/10LS. FIG. 4 is a cross-sectional view illustrating the lid tray 60 fitted over the base tray 30, five extended base posts 33 disposed between each of six egg cells (one row) to form a closed carton.

FIG. 5 shows an interior view of the molded pulp fiber, single-piece base tray 30 that includes a 2×6 rectangular array of 12 base egg cells 31, each cell for holding a single egg E in a generally upright position (see FIG. 11 ). Each cell 31 has a cup shaped recess formed by a sidewall 34 and a bottom wall 35, the recess having an inner surface that is sized and shaped to conform at least in part to the outer ovoid shape of a lower half of the egg that it gently supports in an upright position, shielding the egg from forces that impact the closed carton. Each egg cell bottom wall 35 has a flat annular portion 36 that lies in a horizontal base reference plane BRP, allowing the base tray to sit flat on a store shelf (or on the exterior top wall of a lid of another closed carton on which it rests). The egg cells 31, 31 are joined by connecting walls 37 and extended base posts 33 disposed between the cells that provide strength, stability and support; the cell sidewalls 34 and bottom walls 35 themselves are reinforced by ribs or the like. The open top ends 38 of the cells all lie within a horizontal top reference plane TRP defined by a top wall 39 of the base tray having a generally rectangular perimeter 39P, with a pair of opposing front and rear edges 39F and 39R, and a pair of opposing right and left side edges 39RS and 39LS (that extend between the front and rear edges respectively). The base perimeter 39P, includes on each of the front and rear perimeter edges, six spaced apart moisture venting ports 20, one port opening directly into one each of the respective six egg cells 31 in the front row of cells, and six cells in the rear row of cells, and five spaced apart connector members (e.g., snap-fit or latch) 22B along each of the front and rear perimeter edges, one being disposed between each of two adjacent ports 20 for releasably engaging with the lid perimeter to form a closed carton. The base perimeter 39P, includes on each of the right and left perimeter edges, two spaced apart venting ports 20 and one connector member 22B similarly disposed as on the front and rear perimeters. The elongated base cell posts 33 are disposed beneath the open lid labelling area 70 (in the assembled carton); these are specially sized and shaped to engage the interior of the top wall 71 of the lid labeling area and support it from top compressive forces applied to the two top wall of the lid, so as to prevent such forces from either collapsing the closed carton or crushing the eggs in the open labeling area of the closed carton. In addition, there are provided a plurality of shorter base cell posts 33S disposed along the four sides of the base perimeter 39, with one post 33S positioned between each adjacent pair of cells 31, 31, that engage and support the lid sidewall perimeter.

The base and lid tray 30, 60 perimeters each include respectively, mating releasable connector members 22B and 22L for releasably attaching the lid to the base, such that when the base and lid trays are assembled to form a closed carton (as shown in FIGS. 1-3 ) the mating releasable connector members 22B, 22L provide both enhanced strength and ease of carrying of the assembled carton.

The base and lid trays are separately manufactured, and can be made of different materials. Those materials are selected to enhance ease of packing and transport, and moisture evaporation during and after filling the base tray with eggs.

FIG. 5 also shows the interior of the clear plastic lid tray 60, sized and shaped to mate with the base tray 30, including a rectangular perimeter 60P that matches the overall perimeter 30P of the base tray. The lid provides a labeling area on the top wall 71 of the lid tray. The interior open cavity 73 (surrounded by walls 71 and 72) allows a graphic printed label L to be inserted into the cavity, lying along an interior surface of the flat panel top wall 71 and visible there-through when the clear lid top wall 71 when it is formed of a transparent plastic material. Alternatively, a separate label can be attached to the exterior surface of top wall 71, and the top wall itself can be embossed or printed with labeling information. The open lid labelling area in the assembled carton is supported by the extended base posts 33 that support it from top compressive forces applied to the two top wall of the lid, so as to prevent such forces from either collapsing the closed carton or crushing the eggs in the open labeling area of the closed carton.

FIG. 5 illustrates interior views of the base and lid trays 30, 60 respectively, in an open position, with the bottom wall 35 of the base tray 30 resting on a flat supporting surface and the top wall 65 of the lid tray 60 resting on another flat supporting surface. FIG. 5 shows the column of five aligned extended base tray cell posts 33, and shorter height posts 33S disposed at the base perimeter along the opposing front and rear and opposing right and left side edges of the base tray perimeter, that will support the open lid labeling area 73, when the lid and base trays are in the closed position. The open area 73 in the lid tray is a generally rectangular shaped recess with flat bottom wall 71 (to receive a labeling insert L), visible through the lid top wall 71 when the tray is formed of transparent plastic, and a rectangular sidewall 72 that surrounds the top wall for supporting the top wall.

Other Embodiments

FIGS. 6-8 show a two-piece (separate base 110 and lid 140) egg carton assembly 105 having mating base and lid rectangular perimeters 116,144 that are releasably sealed (e.g., by temporary adhesive) according to another embodiment of the invention. The assembly includes a base 110 providing a 2×6 array of full depth egg cells and moisture venting ports 120 on the base perimeter, and a flat lid 140 removably sealed about the perimeter of the base. The flat lid provides an enlarged flat planar expanse (top wall 142) for displaying graphics or text relating to product source and/or product information. A temporary (releasable) sealing member 150 (e.g., an adhesive coating) is disposed between and connecting the rectangular lid perimeter and the base upper sidewall rectangular perimeter when the carton is filled with eggs to form the closed carton.

As shown in FIG. 7 , the interior of the egg carton base 110 is provided with support features to accommodate an array of eggs E, each in an individual egg cell 114, here a rectangular 2×6 array of 12 egg cells. After filling the base carton with eggs, a flat top lid 140 is sealed at the lid perimeter to the perimeter of the base. In this embodiment, the egg cells of the base extend at least the full height (in the vertical direction transverse to the BRP) of the eggs (disposed vertically in the cells).

The 12 egg cells 114 of the base carton each have a closed bottom wall 112 that is configured to rest on a base reference plane BRP (e.g., a horizontal base reference plane with the base carton in a horizontal orientation). Each egg cell 114 has a sidewall wall extending upwardly from the base wall in a generally transverse direction T to the BRP, the sidewall and base wall together forming an egg chamber or cell 128 that is open at a top end 113 (opposite the closed bottom wall 112) and surrounded by the sidewall and bottom wall. The perimeters of the open top ends 113 of the cell sidewalls all lie within a top base wall 117, the top base wall 117 connecting the adjacent cell perimeters, and the top base wall having an upper sidewall perimeter 116 configured to be sealed to a mating perimeter of the lid, e.g., by a hot melt seal or adhesive. The rectangular perimeters 116 and 144 of the base and lid are disposed in a top reference plane (TRP) that is parallel to the BRP.

The egg cells 114 are configured to support and hold the egg cells in a vertical orientation with respect to the horizontal BRP. The egg cells include a plurality of arced supporting structures or posts 133, disposed between and connecting two aligned front and rear egg cells. The bottom wall 112 of each egg cell may include flexible or cushioning elements 130 (see FIG. 9 ) that assist in holding each egg vertically (transverse to BRP) such that the longitudinal egg centerline ECL is aligned in the transverse direction T.

FIGS. 10-12 show a two-piece (separate base 210 and lid 240) egg carton assembly 205 according to another embodiment of the invention, the assembly including a base providing a 2×6 array of egg cells 214, and a lid 240 removably sealed about the perimeter of the base and providing an enlarged flat top planar expanse (top wall 242) and four enlarged flat planar side walls 248 (front and rear, and left and right sides) for displaying graphics or text relating to product source and/or product information.

The base includes an array of 12 egg cells 214, including six front cells 214F and six rear cells 214R arranged in a rectangular 2×6 array. Each cell 214 has a closed bottom wall 212 lying in a horizontal base reference plane BRP and a cup-shaped sidewall 215 extending upwardly (in the vertical direction transverse to the BRP) from the closed bottom wall 212 to an open top end 213. A planar top base wall 217 connects the perimeters of the open top ends 213 of the cells, the top wall having an upper sidewall perimeter 216P lying in a horizontal top reference plane, parallel to the BRP. Supporting or cushioning members 230 are disposed in the bottom wall 212 of each egg cell 214 for holding an egg upright in the egg cell, with a central longitudinal axis of the egg ECL aligned with the transverse direction T.

The egg carton lid 240 includes a top lid wall 242, having a top wall perimeter 244, the top wall comprising a flat planar expanse that extends over substantially all of the area bounded by the top wall perimeter 244. Four lid sidewalls 248 extend downwardly from the perimeter of the lid top wall that together with the lid top wall 242 define an internal chamber 245 in which the upper ends of the eggs are disposed (the lower ends of the eggs being disposed and held vertically upright by the egg cells 214 in the base 210).

A removable attachment member 243 (e.g., a mating flange and lip as shown in FIG. 11 on the mating perimeters of the base 216P and lid 248P) is disposed between and removably connects the lid and base when the carton is filled with eggs and in the closed (assembled) position.

In this embodiment (FIGS. 10-12 ), the sidewalls 215 of the base egg cells 214 are less than the full egg height FEH in the transverse direction T, here about half the egg height (as shown in FIG. 11 ). In the assembly 205, the lid 240 has an interior lid chamber 245 formed by the closed top wall 242 and four lid sidewalls 248F (front), 248R (rear), 248RT (right hand side) and 248LT (left hand side) that extend downwardly from the four sides respectively of the planar top wall 242, providing an open space above each egg cell 214 such that together the base cells and lid chamber extend at least the full height FEH of a vertically disposed egg in the assembled base and lid. In one embodiment the lid is made of a clear plastic, such as polyethylene terephthalate (PET), optionally recycled PET, to provide visual clarity and a clear view of the eggs in the filled and assembled carton.

In various embodiments, the base and lid may be made of different materials and/or different configurations. The base and/or lid may be made from cardboard, pulp fiber, plastic foam or solid plastic. Pulp cartons are usually made from a mixture of paper, water and fibers; they are typically biodegradable and inexpensive to produce (mixing huge vats of water and paper into a thick slurry that is piped into molds where the components are formed and allowed to dry). Foam cartons are made from small plastic beads (typically polystyrene) that are melted and molded into the component shape. Not all recycling streams accept polystyrene. Clear plastic cartons are typically made of a thin layer of solid plastic such as PET; the plastic is heated and pressed into molds to form the component. PCT is lightweight and recyclable.

In various embodiments the base and lid may comprise:

a) a shallow base made of pulp, and a dome lid (the dome lid being made of pulp, plastic or cardboard);

b) a shallow base made of plastic (e.g., PET), and a dome lid (the dome lid being made of pulp, plastic or cardboard);

c) a deep base made of pulp, and a flat lid (the flat lid being made of pulp, plastic or cardboard);

d) a deep base made of plastic (e.g., PET), and a flat lid (the flat lid being made of pulp, plastic or cardboard).

In various embodiments, the base and lid may comprise different colors. This embodiment would allow an egg packer to have separate inventories for bases that could be used in combination with different lids. In various embodiments, the different bases or lids would be customized to different sources (brands) of eggs.

In various embodiments, providing a variety of egg carton designs enables a retailer (e.g., store) carrying different brands/sources of eggs to provide a distinguishing point of sale feature, e.g., for ease of identification by the retailer and/or customer. between such different brands/sources.

In various embodiments, providing a variety of egg carton designs made of different materials and/or configurations would enable the retailer to select a lid and/or base with a desired level of protection against moisture for preservation of the carton and eggs (enhancing shelf life, depending upon the individual conditions in a particular retailer display case and/or under particular shipping or storage conditions).

In various embodiments, providing a variety of configuration of the lid and base would enable an egg packer to achieve higher packaging efficiency, less changeovers, more flexibility, lower inventory (e.g., use of the same base with multiple different lids).

In various embodiments, the base carton and/or the lid allows the combined egg carton assembly to provide a broader arrange of options to the consumer, such as the ability of the user to reduce package volume of the carons when discarding them. In contrast, the standard hinged one-piece carton occupies considerable disposal space.

In various embodiments, the flat lid provides a large area for labeling or branding.

In various embodiments, the lid and/or base is made of a clear plastic that allows for visual inspection or viewing of the contents of the closed assembly, e.g., the eggs held therein.

In various embodiments, the carton provides a distinguishing feature that consumers may easily identify with particular sources of eggs on the grocery shelves.

In various embodiments, the base carton can have various numbers of egg cells (e.g. 6, 8, 9, 10, 12, 15, 20) arranged in various configurations (e.g., a rectangular array of parallel rows and parallel columns (e.g., 3×3, 3×4, 3×6, 4×5, 4×6), or a zig-zag, slanted or otherwise angled array with or without symmetrical placement of the egg cells in the array).

In one embodiment of the present invention, one or both of the base tray and lid tray are made of molded pulp fiber. In other embodiments, one or both of the base tray and lid tray are made of a solid thermoplastic material, such as a polyester, and more preferably a transparent thermoplastic material enabling a customer to view the eggs and/or labeling material inside of the closed carton. A suitable polyester is polyethylene terephthalate (PET), including both homopolymers and copolymers, virgin and recycled materials. Each of the lid and base trays can be molded from a solid sheet of polyester, for example by pressing the solid sheet between male and female dies to form the base cells (or lid cells and label area) and other structural and/or ornamental features of the base tray (or lid tray or integral base and lid trays with hinge connection), and then removing (trimming) any remaining portions of the sheet to from the base tray (or cell tray, or integral cell and base tray with hinge connection). Other suitable plastic materials for forming a solid lid and base trays include polyolefin (e.g., polyethylene (PE), polypropylene (PP)), and poly(lactic acid (PLA), including homopolymers, copolymers, mixtures and blends thereof, and including virgin and reclaimed (recycled) materials. In some embodiments, the plastic lid and/or base trays are opaque (not transparent).

In general, each base cell has a vertical cell axis, aligned with the long axis of the egg and perpendicular to the base plane in which the bottom walls of the base cells reside, and an outwardly bowed sidewall portion sized to receive a major horizontal cell diameter (transverse to the long axis) of the egg.

In various embodiments, an egg carton is provided having structural features that enable packaging of larger size eggs, e.g., large, extra-large, or jumbo eggs in a rectangular array, in both oriented and non-oriented positions, while allowing for easy filling, closing, handling and packing into shipping containers. As used herein, large eggs fall in a weight range of about 54-61 grams per egg, extra-large eggs fall in a range of about 61-68 grams per egg, and jumbo eggs fall in a range of about 68-77 grams per egg. The carton may be configured to hold a variety of smaller sized eggs, namely small (about 40-47 grams) or medium eggs (about 47-54 grams), and alternative super jumbo eggs (greater than about 77 grams). Preferably, the carton can be used with standard egg grade equipment and the carton will fit into standard cases (containers, such as corrugated paper, wire or plastic cases) designed for holding a plurality of egg cartons.

In various embodiments, the assembled base and lid trays form a plurality (e.g., a 2×6 array) of individual egg cell pockets that can accept the larger, heavier and more fragile extra-large eggs in both oriented (large diameter down toward the bottom of the base cell) and non-oriented (larger diameter up toward the top of the base cell) positions, versus prior art containers that require a correct (oriented, larger diameter down) positioning in the cells. The base and lid trays include a larger cell construction able to hold an extra-large egg that is non-oriented, i.e., enabling the largest diameter of the egg to fit into the base cell). By accommodating both oriented and non-oriented eggs, this allows more efficient processing, carton handling and placement into master containers (packing cases).

An apparatus and method for making solid plastic trays are known, for example including a female mold cavity and a plug assist for pressure forming a base tray or lid tray with a turned up lip edge, in the mold. A continuous sheet of plastic is fed to the mold and is formed by the plug assist pushing the sheet toward the female cavity in combination with the application of a vacuum on the exterior side of the sheet/carton to draw the sheet into the recesses of the mold cavity. The formed carton is then trimmed at a separate trim station, where the tray is positioned between the female die cavity and a cutting edge punch having a knife edge, the cavity and punch being brought together to sever (cut) the lip edges from the sheet to form the terminal ends of the lip edges, in a direction aligned with the vertical height H direction of the carton. Other forming and trimming methods known to those skilled in the art can be used for forming the carton and turned up lip edge of a base or lid tray according to the present invention. 

1. A rectangular perimeter egg carton comprising: a lid, and a base separate from the lid, wherein the lid and base are assembled together to from a closed egg carton, the base having a top wall and a rectangular array of recessed base cells arranged in rows and columns depending from the top wall, each base cell having an open top end, a sidewall and a closed bottom wall and being sized and shaped to hold one egg in a generally upright position with the long axis of the egg disposed in a vertical direction transverse to a base reference plane in which the bottom walls of the base cells reside; the base and lid having respective mating rectangular perimeter edges, including opposing front and rear side edges and opposing left and right side edges, that mate with each other in a closed position to from the rectangular perimeter egg carton for enclosing an egg in each of the respective cells; and a plurality of spaced apart venting ports formed in each of the perimeter side edges of one or more of the base and lid perimeters for releasing moisture from the closed egg carton.
 2. The rectangular perimeter egg carton of claim 1, wherein the venting ports each comprise a groove formed in the base along each of the base perimeter edges.
 3. The rectangular perimeter egg carton of claim 1, wherein there is at least one venting port disposed in the sidewall of each cell of the base.
 4. The rectangular perimeter egg carton of claim 1, wherein the venting ports each comprise an outwardly projecting grooved surface, extending outwardly from the outer surface of the cell sidewall.
 5. The rectangular perimeter egg carton of claim 1, wherein the lid and base perimeter edges include releasable connectors for removably attaching the lid to the base to temporarily seal an egg in each cell of the closed carton.
 6. The rectangular perimeter egg carton of claim 5, wherein the releasable connectors are disposed between each pair of adjacent cells on each of the mating perimeter edges.
 7. The rectangular perimeter egg carton of claim 5, wherein the releasable connectors comprise snap-fit tabs on the lid perimeter edges that extend over the base perimeter edges.
 8. The rectangular perimeter egg carton of claim 5, wherein at least one of the venting ports is disposed between each adjacent pair of the releasable connectors.
 9. The rectangular perimeter egg carton of claim 1, wherein the sidewalls of two adjacent cells form a cell divider which prevents contact between eggs in the adjacent cells.
 10. The rectangular perimeter egg carton of claim 1, wherein the base includes a base top wall forming a flat planar surface that extends between the open top ends of the cells and forms the base perimeter edges.
 11. The rectangular perimeter egg carton of claim 1, wherein the base includes cell posts disposed between four adjacent cells in the rectangular array of cells.
 12. The rectangular perimeter egg carton of claim 11, wherein the lid comprises a lid top wall disposed parallel to the base reference plane on which the cell base walls reside, and lid sidewalls extending downwardly between the lid top wall and the lid perimeter edges to form an interior chamber for enclosing an upper portion of the eggs disposed in the cells of the base.
 13. The rectangular perimeter egg carton of claim 12, wherein the base cell posts extend above the base perimeter edges and into the interior chamber and mate with an inner surface of the lid top wall to strengthen the closed egg carton.
 14. The rectangular perimeter egg carton of claim 1, wherein the sidewalls of the base cells extend the full height of the eggs disposed in the cells, and the lid comprises a flat planar lid top wall that is sealed about its perimeter edges to the mating perimeter edges of the base.
 15. The rectangular perimeter egg carton of claim 1, wherein the sidewalls of the base cells extend less than the full height of the eggs disposed in the cells, and wherein the lid comprises a lid top wall disposed parallel to the base reference plane on which the cell base walls reside, and lid sidewalls extending downwardly between the lid top wall and the lid perimeter edges to form an interior chamber for enclosing an upper portion of the eggs disposed in the cells of the base.
 16. The rectangular perimeter egg carton of claim 1, wherein the array of cells comprises one of a 2×3, 2×4, 2×5, 2×6, 3×3, 3×4, 3×5, 3×6, 4×4, 4×5, 4×6, 5×5, 5×6, or 6×6 rectangular matrix of cells.
 17. The rectangular perimeter egg carton of claim 1, wherein the base and lid are formed of different materials.
 18. The rectangular perimeter egg carton of claim 1, wherein the base is formed of molded pulp fiber, and the lid is formed of a solid plastic.
 19. The rectangular perimeter egg carton of claim 1, wherein the different materials are solid plastic, foamed plastic, and pulp fiber.
 20. The rectangular perimeter egg carton of claim 19, wherein the plastic is one or more of polystyrene, polyester, polyethylene, or polylactic acid, including polymers, copolymers, mixtures and blends thereof. 